Phenolic condensation products and process for preparing same



' lowed by operation.

Patented Dec. '3, 1929' I UNITED" STATES oscan a. cnmmr, or cnrcaeo,

rnnnomc commiwsa'rron rnonuc'rs No Drawing.

The present invention relates to improvements in methods for. producingphenoliccondensation products.

More particularly the present invention relates to improvements inmethods for the production of material from the condensation of phenolicbodies and formaldehyde which material is adapted for casting. Thepresent invention relates particularly to the production of materialsuitable for the casting of transparent articles.

An object of the present invention is to provide an improved processwhich will materiall reduce the length of time required for boiling thephenolic body and the formaldehyde, tion of the product, and forreducing the loss of formaldehyde which is unavoidable even with the useof reflux condenser-s.

A further object is to provide an improved method for the production ofmaterial for manufacturing transparent cast articles,

which improved method will reduce the cost.

from the present figures and which will resultin an improved product.

Further ob'ects will appear as the description proceeds.

It has been proposed to obtain the material for transparent condensationproducts by condensing phenolic bodies in the presence of a small amountof a basic condensing agent such as potassium hydroxide. It has beenfound necessary in this process to add considerable amounts. of alcohol,while distilling off the water which is present in the formal dehydeand which is formed as a result of the reaction. If the alcohol is notadded, rubbery products are often obtained.

It has "also been proposed to condense phenol and formaldehyde withoutthe use of a condensingagent by-prolonged boiling under a refluxcondenser. The'boiling is fola distillation process and a casting Saidprolonged boiling operation, which sometimes exceeds a period of 120hours, is decidedly objectionable.

The present invention contemplates a method according to which theprolonged boiling referred to may be 'obv-iated without decreasing thetransparency of the products.

rumors, rac'runmo couramr or cnrcaoo, rumors,

Application filed April 21,

for reducing the danger of discolora- ASSIGNOB TO ECONOMY FUSE AND MANU-A CORPORATION OF NEW YORK annrnoonss FOR PREPARING sum 1926. Serial mi.108,621.

In fact, the transparency of the resulting product is improved due tothe fact that discoloration which accompanies prolonged boiling ismaterially reduced.

According to the present invention a condensing agent is used, whichcondensing agent is formic acid. By the use of formic acid as acondensing agent, provided a suitable proportion of said formic acid isemployed, the period of boiling under a reflux condenser may be reducedfrom a long period of time to a period of from 1 to 4 hours. Otheradvantages inherent in the use of formic acid as a condensing agent arethe fact that there is no tendency for the initial products to becomerubbery during the distillation process and that substantially all ofthe acid is eliminated with the water during said distillation process.Provided substantiall pure materials are used, the products obtalned areof a fine amber color and have a high degree of transparency. In thefinal state they are infusible and may be readily machined,sandpaperedor buffed.

Applicant is aware that the use of acids has been proposed for themaking of cast articles. A serious objection to the use of acids asheretofore known in this connection, however, has been that even withsmall proportions of acid opaque articles have been obtained. Theseopaque articles can be rendered transparent only by a long carefulheating. According to the present invention, in order to obtaintransparent articles it is only necessary to eliminate substantially allof the water and acid by distillation from the initial condensationproducts. Applicant is aware that commercial formaldehyde containsformic acid in amounts not exceeding .12 of 1 per cent of the weight ofthe solution. This proportion of formic acid is insufficient foraccomplishing the results of the present invention, and the improvedmethod consists in condensing a phenolic body and formaldehyde or othermethylene containing substance in the presence of decidedly greateramountsof formic acid than are present in commercial formaldehydefReferring to figures for purposes of illustration, 200 parts of phenolicbody may be A degrees C., until infusible. The. term eraturev should besuflicient in amount to a thickening of the lower resinous layerliasoccurred.

At this point two procedures are possible. The supernatant Water ma beremoved by distillation, preferably under reduced pressure, whereupon aclear, yiscous, almost colorless mass is obtained; or the supernatantwater may be decanted and an additional quantity of formaldehyde addedto replace that lost by decantation, after which the mixture isdistilled until clear. The advantage of the latter method is that alesser quantity of water needs to be distilled. The viscous transparentproduct referred to is poured into suitable molds and heated attemperatures gradually increased from degrees C. to 90 is then raised to100 degrees C. and nally to about 130 degrees C. The length. of heatingrequired varies vwith the size of-the articles cast.

The process above outlined may be varied,

in that a two-step process maybe used. Ac-

cording to the two-step process, the initial mixture may consist of aphenolic body. for- H110 acid and an insufficient amount of formaldehydeto cause the production of an in fusible body upon continued heating.After heating for a suflicient length of time to cause combination ofsubstantially all of the. formaldehyde with the phenolic body, thesupernatant water may be decanted and an addi tional quantity offormaldehyde may be added. The second quantity of formaldehyde renderthe initial condensation product infusible upon continued heating. It isalso desirable to add an additional quantity of formic acid to replacethat decanted with the "water. This mixture may be distilled with orwithout previous boiling under a reflux condenser, and the condensationproduct may be treated as above described. x

The proportions recited above are merely illustrative and should not beconside'red'in a limiting sense. A lesser amount of formaldehyde willusually give satisfactory results.

The amount of formic acid may be varied over acid used, the reaction. r

In the claims the applicant defines the amount of formic acid employedas being that of an added amount, and by this the applicant means thatthe reaction ofthe phenolic body and the methylene containing substancegreater being the speed of the is conducted in the presence of formicacid in 7 amount greater than that which is normally found in thecommercial methylene containing substances, which are suitable for thisre- .ing th action. It is to be understood that the term added does notnecessarily imply that there is already some formic acid present in themethylene containing substance employed, and in cases where no formicacid ispresent the entireamount is introduced, but in cases where someformic acid is present an additional amount is introduced to bring thequan tity up to the amount desired.

lVhat is claimed is r 1. The method of preparing a material suitable forcasting which consists in heat treating a phenolic body and an activemethylene containing substance in the presence of formic acid, theamount of formic acid being in substantial excess of the amount presentwhen commercial: formaldehyde is employed commercial .ormaldehyde isemployed .to supply the methylene groups, and eliminate aqueous layerformed as a result thereof.

3. The method of preparing a material suitable; for casting whichconsists in heat treating a phenolic body and formaldehyde in thepresence of formic acid, the amount of formic acid being in substantialexcessof-the stantial excess of the amount present when amount presentby virtue of the presence of commercial formaldehyde.

4. The composition of matter produced by heat treating a phenolic bodyand an activemethylene containing substance in the presence of formicacid, the amount of formic acid being in substantial excess of theamount present when commercial formaldehyde is employed to supply themethylene groups.

'Signedat Chicago, Illinois, this 9th day of April, 1926. OSCAR A.CHERRY.

